I would also buy a used one if you can. New oak would be overpowering in any beer. Used liquor barrels show up in the vendors showcase every so often.
Brute Brew Works
Primary: Epic Flemish Brown(15g) waiting to go into a bourbon barrel, Brett C. Blackberry Berliner, lambic waiting for fruit
Secondary: Sour Brown Ale from Black IPA second runnings sitting on 2.5lbs. blackberries and 2.5lbs mulberries
Bottled: Traditional Mead aged on Maker's 46 soaked oak, Brett Maibock